KubernetesExecutor can start stale worker pods for obsolete TaskInstance UUIDs under HA schedulers

### Under which category would you file this issue? Airflow Core ### Apache Airflow version 3.3.0 ### What happened and how to reproduce it? Basically, we got 19 failed retries for example in a single Task all of them are failed because another Scheduler created the same task, so, using HA increases the frequency of happening this issue. This delayed our task finishing successfully for more than 30 minutes. <img width="1648" height="1345" alt="Image" src="https://github.com/user-attachments/assets/7425757e-1247-4a27-ba42-680b43d106bf" /> When running Airflow 3.3.0 with `KubernetesExecutor` and multiple scheduler replicas, we observed stale Kubernetes worker pods starting after the corresponding `TaskInstance` row had already been replaced/retried. The stale worker pod then calls: ```http PATCH /execution/task-instances/{task_instance_id}/run and the execution API returns: { "detail": { "reason": "not_found", "message": "Task Instance not found" } } ``` The worker logs this as a generic ServerResponseError. The important detail is that the missing {task_instance_id} is an immutable TaskInstance.id UUID from an older queued workload. Looking up the same logical task by (dag_id, task_id, run_id, map_index) shows a newer TaskInstance.id with a higher try_number already queued. Observed sequence: 1. Scheduler A queues a task instance with UUID A, try 1. 2. Kubernetes pod creation/start is delayed, for example due to cluster quota/resource pressure. 3. Another scheduler/retry path moves the same logical task forward and queues a replacement task instance with UUID B, try 2. 4. The old Kubernetes pod for UUID A eventually starts. 5. The worker calls /execution/task-instances/A/run. 6. The API returns 404 not_found because UUID A no longer exists. 7. The worker fails during startup with ServerResponseError. This appears to be a race between the scheduler/executor queue, Kubernetes pod startup latency, and HA scheduler retry/reconciliation. Relevant source behavi…